//NaN
console.log(NaN === NaN, "NaN === NaN");
console.log(typeof NaN, "NaN类型");
console.log(NaN == false, "NaN == false");
//null
console.log(null === null, "null === null");

//undefined
console.log(undefined === undefined, "undefined === undefined");

//Symbol
console.log(Symbol.for('a') === Symbol.for('a'), "Symbol.for('a') === Symbol.for('a')");

//[]
console.log([] == false, "[]==false"); //true
console.log([] === false, '[] === false'); //false
console.log(typeof [], '[]类型'); //object
console.log([] == [], "[]==[]");